1. Field of the Invention
The present invention relates to a semiconductor device, a fabrication method and an operating method thereof, and more particularly, to a programmable and erasable digital switch device, a fabrication method and an operating method thereof.
2. Description of the Related Art
An integrated circuit usually includes programmable devices. These programmable devices control the connection of devices in the circuit. These programmable devices are fuses or antifuses.
Fuses are adapted to connect main memory cell arrays and redundancy memory cell arrays. If partial memory blocks in the main memory cell arrays fail and cannot be repaired, fuses are burned out by an electric current or a laser to change the connection among the remaining normal memory cell arrays. The redundancy memory cell arrays then replace the failed memory cell arrays to provide the normal operation of the memory.
Antifuses connect transistors of gate arrays of a logic circuit. It means that each transistor of a gate array is coupled to an antifuse. While the gate arrays are programmed, a high voltage is applied to the antifuses so that dielectric layers of the antifuses are broken through. At this moment, the antifuses are in the “on” state. If no voltage is applied, the antifuses are in the “off” state. Accordingly, the programming of the antifuses is determined by whether the voltage is applied to the antifuses so as to make the antifuses “on” or “off”. Therefore, the gate arrays are programmed.
However, either fuses or antifuses can only be programmed once. It means that the programming is not reversible. Their applications thus are limited. In addition, electric current or laser burning out fuses or breakdown of dielectric layers of antifuses is required for the programming operation. These operations may damage other devices.